Faecal Elastase 1 Concentration Is a Marker of Duodenal Enteropathy M G Schäppi, V V Smith, D Cubitt, P J Milla, K J Lindley

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ORIGINAL ARTICLE Arch Dis Child: first published as 10.1136/adc.86.1.50 on 1 January 2002. Downloaded from Faecal elastase 1 concentration is a marker of duodenal enteropathy M G Schäppi, V V Smith, D Cubitt, P J Milla, K J Lindley ......

Arch Dis Child 2002;86:50–53

See end of article for authors’ affiliations Background: Measurement of faecal elastase (FE1) is used widely to screen for pancreatic exocrine ...... insufficiency (PI). FE1 does not allow differentiation of primary from secondary PI. Correspondence to: Aims: To investigate the relation between duodenal morphology and FE1 in children with secondary Dr K J Lindley, PI resulting from primary gastrointestinal diseases. Gastroenterology Unit, Methods: A group of 51 children underwent small intestinal biopsy and FE1 measurement. Villus to Institute of Child Health, 30 Guilford Street, London crypt ratio (VCR) and inflammation within the lamina propria of duodenal mucosal biopsy specimens WC1N 1EH, UK; were scored and compared with FE1 values. [email protected] Results: In 51 children from nine diagnostic categories, a highly significant correlation between FE1 Accepted for publication and both duodenal morphology and inflammation was found. 4 October 2001 Conclusion: Small bowel enteropathy is associated with low FE1 concentrations, indicative of second- ...... ary exocrine pancreatic insufficiency.

easurement of faecal elastase 1 (FE1) concentration is 500 a simple, non-invasive, and widely available test, which allows clinicians to estimate pancreatic exo- 400 M µ g/g) crine function. It has been shown to be a useful screening test for severe primary pancreatic insufﬁciency, in conditions such 300 as cystic ﬁbrosis or Shwachman’s syndrome.1–5 Reduced FE1 concentrations are found in some individuals with coeliac 200 disease.6–8 A variety of enteropathic processes other then coeliac disease are associated with reduced excretion of faecal 100 elastase. We have therefore studied the relation between duo- FE1 concentration ( 0

denal morphology, duodenal inﬂammation, and FE1. 321 456789 http://adc.bmj.com/ Disease groups

PATIENTS AND METHODS Figure 1 FE1 concentrations in different diagnostic groups. 1 = Patients autoimmune enteropathy; 2 = idiopathic inflammatory bowel Retrospective analysis was undertaken of all children between disease, 3 = indeterminate enteropathy, 4 = food sensitive March 1997 and February 2000, who had undergone (1) small enteropathy, 5 = food allergy without enteropathy, 6 = intestinal biopsy and (2) FE1 measurement within a month of post-infectious enteropathy, 7 = tufting enteropathy, 8 = short gut syndrome, 9 = failure to thrive without GI cause. FE1 concentrations: each other at Great Ormond Street Hospital. <15–100 = severe exocrine pancreatic insufficiency; 101–200 = on September 27, 2021 by guest. Protected copyright. moderate; >200 = normal. Range <15 to >400. Faecal elastase 1 FE1 concentrations were measured using an enzyme linked IU/kg), which stimulate pancreatic ductal and acinar secretion immunosorbent assay (ELISA) kit, which uses two mono- respectively. Duodenal juice volume, pH, bicarbonate, lipase, and clonal antibodies against two distinct epitopes of human pan- trypsin concentrations were determined in the laboratory.11 creatic FE1 (Schebo Tech, GmbH, Wettenberg, Germany). The assay is linear between 15 and 400 µg elastase per g faecal Duodenal histology weight with a lower detection limit of 15 µg/g. Results were Histological sections of duodenal mucosa stained with expressed as µg/g of stool and nominally scored as indicative haematoxylin and eosin (H&E) were examined by light of normal pancreatic exocrine function (>200 µg/g), moderate microscopy in a double blind fashion by an experienced pancreatic exocrine insufficiency (100–200 µg/g), or severe paediatric histopathologist and a paediatric gastroenterolo- 14 pancreatic exocrine insufficiency (<100 µg/g). Excessive gist. The morphology was assessed by measuring villus to stool water may be associated with falsely low faecal elastase crypt ratio (VCR) and scored in the following manner: 0 = flat 910 results and liquid stool samples were therefore discarded. mucosa, 1 = severe partial villous atrophy (PVA) (1:1 VCR), 2 = moderate PVA (1.5:1 VCR), 3 = mild PVA (2–2.5:1 VCR), 4 Secretin–cholecystokinin (CCK) test = normal VCR. Inflammation within the lamina propria of the In a small number of children, with a faecal elastase less than biopsy specimens was scored (3 = no inflammation present, 2 200 µg/g, the secretin–CCK test, a direct test of pancreatic exo- = mild infiltrate of plasma cells, 1 = notable infiltrate). crine function,11 was performed. For this a tube was placed under fluoroscopy in the third part of the duodenum. Duodenal juice was aspirated over a 15 minute period and collected in ...... plastic tubes on ice. Further samples were collected during con- Abbreviations: CCK, cholecystokinin; FE1, faecal elastase; GI, secutive 15 minute periods following injection of intravenous gastrointestinal; PI, pancreatic exocrine insufficiency; PZ, pancreozymin; secretin (2 IU/kg), and subsequently intravenous CCK (2 PVA, partial villous atrophy; VCR, villus to crypt ratio

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Table 1 Comparison of faecal elastase 1 concentration with duodenal morphology Arch Dis Child: first published as 10.1136/adc.86.1.50 on 1 January 2002. Downloaded from

FE1 levels (µg/g)

Morphology >200 100–200 <100

Normal mucosa 10 food allergy 3 food allergy 1 post-infectious (score 4) 2 post-infectious 1 AIE 4 FTT 1 FSE 2AIE 1SGS 1IE Total 19 (31.7%) 6 (10%) 1 (1.7%)

Mild PVA 1 FSE 1 AIE 1 FSE (score 3) 1 SGS 1 food allergy 1 SGS Total 2 (3.3%) 3 (5%) 1 (1.7%)

Moderate PVA 2 AIE 1 IE 2 FSE (score 2) 1 AIE 1IE Total 2 (3.3%) 1 (1.7%) 4 (6.7%)

Severe PVA 1 AIE 2 SGS 4 AIE (score 1) 1 tufting 2 IBD 2 SGS Total 1 (1.7%) 3 (5%) 8 (13.3%)

Flat mucosa 2 AIE 2 AIE 2 IE (score 0) 1 IE 1 tufting 1 tufting Total 2 (3.3%) 4 (6.7%) 3 (5%)

Total 26 (43.3%) 17 (28.4%) 17 (28.4%) 7AIE 4AIE 5AIE 10 food allergy 4 food allergy 3 IE 4 FTT 4 SGS 2 IBD 2 post-infectious 2 IE 2 SGS 1 FSE 2 tufting 3 FSE 1 SGS 1 FSE 1 post-infectious 1 IE 1 tufting

Morphology: 4 = normal VCR; 3 = 2–2.5:1 VCR; 2 = 1.5:1 VCR; 1 = 1:1 VCR; 0 = flat mucosa. PVA, partial villous atrophy; AIE, autoimmune enteropathy; FSE, food sensitive enteropathy; FTT, failure to thrive without GI cause; IBD, idiopathic inflammatory bowel disease; SGS, short gut syndrome; IE, indeterminate enteropathy; tufting, tufting enteropathy (epithelial dysplasia). http://adc.bmj.com/

Statistical analysis with enteropathies. Of the 17 (28.4%) stool elastase concen- Statistical analysis was performed using t test and regression trations between 100 and 200 µg/g, six (35.3%) had normal analysis. histology and 11 (64.7%) enteropathies. Of the 17 (28.4%) stool elastase concentrations below 100 µg/g, only one (5.9%) RESULTS had normal mucosa and 16 (94.1%) had enteropathies. In A total of 51 patients (24 boys, 27 girls; aged 27 days to 12 patients with normal small bowel morphometry and low FE1, on September 27, 2021 by guest. Protected copyright. years) fulfilled the study entry criteria. FE1 was measured 60 we found inflammation to be present in 6/7 (85.7%), times in 51 patients within a month of duodenal biopsy, nine compared with 4/19 (21.1%) of patients with normal patients having undergone both investigations a second time morphology and normal FE1. Table 1 summarises these results during a subsequent investigative episode. The intravenous according to clinical diagnosis. secretin–CCK stimulation test had been undertaken in six of Inflammation was found to correlate with concentrations of 51 patients during this same period. FE1 (fig 3, table 2). Linear regression analysis showed the The patients fell into nine diagnostic categories based on clinical and histopathological criteria: autoimmune enteropathy, indeterminate enteropathy, post-infectious enteropathy, 500 tufting enteropathy, food sensitive enteropathy, food allergy 400 without enteropathy, short gut syndrome with enteropathy, µ g/g) idiopathic inflammatory bowel disease (Crohn’s disease), and failure to thrive without gastrointestinal (GI) cause. Figure 1 300 shows stool elastase concentrations for each of the diagnostic 200 groups. When mucosal morphology was compared with concentra- 100 tions of FE1, using linear regression analysis, a highly signifi- FE1 concentration ( cant correlation was shown between faecal elastase and duo- 0 denal morphology (t ratio 4.55; p < 0.0001; fig 2, table 1). 4 32 01 Twenty six estimations were compatible with normal exocrine Morphology score pancreatic function (>200 µg/g), 17 with moderate (100–200 Figure 2 Comparison of FE1 concentration with duodenal µg/g), and 17 with severe (<100 µg/g) pancreatic insufficiency. morphology. 4 = normal VCR, 3 = 2–2.5:1 VCR (mild PVA), 2 = Of the 26 normal results, 19 (73.1%) were matched with nor- 1.5:1 VCR (moderate PVA), 1 = 1:1 VCR (severe PVA), 0 = flat mal duodenal mucosal biopsy specimens and seven (26.9%) mucosa.

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Table 2 Comparison of faecal elastase 1 concentration with duodenal Arch Dis Child: first published as 10.1136/adc.86.1.50 on 1 January 2002. Downloaded from inflammation

FE1 levels (µg/g)

Inflammation >200 100–200 <100

No inflammation 7 food allergy 1 food allergy 2 AIE (score 3) 4 FTT 2AIE 2 post-infectious 1FSE 1 SGS Total 17 (28.3%) 1 (1.7%) 2 (3.3%)

Moderate infiltrate 3 food allergy 3 food allergy 3 FSE (score 2) 2 AIE 3 SGS 2 AIE 2 tufting 1 IBD 2AIE 1IE 1IE 1FSE Total 5 (8.3%) 12 (20%) 7 (11.7%)

Severe infiltrate 3 AIE 2 AIE 2 SGS (score 1) 1 IE 1 IE 2 IE 1 SGS 1 IBD 1AIE 1 post-infectious 1 tufting Total 4 (6.7%) 4 (6.7%) 8 (13.3%)

Total 26 (43.3%) 17 (28.4%) 17 (28.4%) 10 food allergy 4 food allergy 5 AIE 7AIE 4SGS 3FSE 4 FTT 4 AIE 3 IE 2 post-infectious 2 tufting 2 IBD 1 FSE 2 IE 2 SGS 1 SGS 1 FSE 1 post-infectious 1 IE 1 tufting

PVA, partial villous atrophy; AIE, autoimmune enteropathy; FSE, food sensitive enteropathy; FTT, failure to thrive without GI cause; IBD, idiopathic inflammatory bowel disease; SGS, short gut syndrome; IE, indeterminate enteropathy; tufting, tufting enteropathy (epithelial dysplasia).

association to be statistically significant with a t ratio of 4.10 driven by neurohumoral events dependent on the presence of http://adc.bmj.com/ (p = 0.0001). Of the 26 normal FE1 results, 17 (65.4%) patients food within the duodenal lumen. Nutrient sensing is had no inflammation. Of 34 low FE1 results 31 (91.2%) had evi- undertaken both by vagal afferent nerves and by mucosal dence of mucosal inflammation within the duodenum. Only enteroendocrine cells. Enteroendocrine cells secrete chole- 3/60 (5%) with low FE1 results had no evidence of small intes- cystokinin in response to intraduodenal lipid/proteins, which tinal inflammation within this selected group of patients. Of 17 stimulates pancreatic acinar secretion of zygmogens. patients with no inflammation and normal FE1, 16 (94.1%) had Many methods are available to measure either directly or normal small intestinal morphometry. indirectly pancreatic exocrine function. Direct methods are Results of direct secretin–CCK stimulated pancreatic secre- labour intensive and invasive. They are best undertaken in on September 27, 2021 by guest. Protected copyright. tion revealed post-stimulation trypsin/lipase levels in the nor- centres in which there is a regular clinical need for the inves- mal range for six patients, showing that their pancreas could tigation so that staff and laboratory alike are competent in respond normally to physiological humoral stimuli. carrying out the investigation. Indirect methods include measurement of pancreatic digestive activity (PABA test, 13C DISCUSSION triglyceride breath test12) or measurement of pancreatic The exocrine pancreas secretes digestive enzymes (acinar tis- enzymes in the stool (faecal chymotrypsin and elastase). Most sue) and bicarbonate (ductal tissue). The secretory process is suffer shortcomings relating to the complexity of the test and/or poor sensitivity/specificity. In recent years faecal 500 elastase determination has become a popular screening investigation for pancreatic exocrine insufficiency because it is 400 simple, cheap, reliable, and widely available. Elastase 1 is pro- µ g/g) duced by the acinar cell of the pancreas and is not degraded 300 during intestinal transit. Hence stool content of FE1 reflects its secretion by the pancreas. FE1 is enriched about fivefold in 200 faeces compared to duodenal juice as a result of faecal dehydration.13 14 The FE1 assay is not affected by 15 16 1 100 temperature or pancreatic replacement therapy, with low

FE1 concentration ( individual inter-day, inter-assay, and intra-assay 0 variations.31517 During the first month of life faecal elastase 3 21 concentrations increase to a plateau of >400 µg/g,17 rendering Inflammation score the assay well suited to the paediatric age range. The assay is Figure 3 Comparison of FE1 concentration with duodenal reported to have a high sensitivity and specificity in diagnos- 1418 inflammation. 3 = normal mucosa, 2 = moderate infiltrate, 1 = ing severe primary pancreatic exocrine insufficiency severe infiltrate. (93–100% sensitivity, 83–100% specificity515171920) when

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2 Walkowiak J, Cichy WK, Herzig KH. Comparison of fecal elastase-1 values of <200 µg/g are used to indicate pancreatic Arch Dis Child: first published as 10.1136/adc.86.1.50 on 1 January 2002. Downloaded from insufficiency. Patients with small bowel mucosal damage, in determination with the secretin-cholecystokinin test in patients with cystic fibrosis. Scand J Gastroenterol 1999;34:202–7. association with coeliac disease, have also been found to have Phillips IJ 6–8 21 3 , Rowe DJ, Dewar P, et al. Faecal elastase 1: a marker of low FE1 concentrations, which increase to normality with exocrine pancreatic insufficiency in cystic fibrosis. Ann Clin Biochem the restoration of the mucosa integrity on a gluten free diet.7 1999;36:739–42. Our study in children with reduced stool elastase and normal 4 Wallis C, Leung T, Cubitt D, et al. Stool elastase as a diagnostic test for CCK–PZ tests provides evidence that the secretory capacity of pancreatic function in children with cystic fibrosis. Lancet 1997;350:1001. the pancreas is normal in individuals with enteropathy. Thus 5 Gullo L, Graziano L, Babbini S, et al. Faecal elastase 1 in children with the most likely mechanism of functional PI is a reduction in cystic fibrosis. Eur J Pediatr 1997;156:770–2. pancreatic stimulation with impaired secretion of secretin or 6 Carroccio A, Iacono G, Ippolito S, et al. Usefulness of faecal elastase-1 CCK by the inflamed intestine.7 There remains a possibility of assay in monitoring pancreatic function in childhood coeliac disease. Ital reduced pancreatic exocrine synthesis as a result of long J Gastroenterol Hepatol 1998;30:500–4. 8 7 Nousia-Arvanitakis S, Karagiozoglou-Lamboudes T, Aggouridaki C, et standing malnutrition or primary pancreatic impairment. al. Influence of jejunal morphology changes on exocrine pancreatic 15 12 Low values of FE1 and other pancreatic enzymes have been function in celiac disease. J Pediatr Gastroenterol Nutr 1999;29:81–5. noted in other primary GI mucosal diseases and regarded as 8 Gomez JC, Moran CE, Maurino EC, et al. Exocrine pancreatic either false positive results22–24 or just been discarded. insufficiency in celiac disease. Gastroenterology 1998;114:621–2. This study clearly shows that small intestinal enteropathy 9 Gullo L. Faecal elastase 1 in chronic pancreatitis. Gut 1999;44:290. 10 Fischer BP, Wehler M, Müller M. Elastase-1 in feces: lyophilization of of various origins is associated with reduced excretion of fae- stool samples may prevent false low results in diarrhea. Gastroenterology cal elastase. The presence of inflammation within the duode- 1998;114:A457. nal mucosa has a profound negative effect on the exocrine 11 Milla PJ, Wozniak ER. Investigatory techniques. In: Milla PJ, Muller DPR, pancreatic function. The link between mucosal inflammation eds. Harries’ paediatric gastroenterology. London: Churchill Livingstone, 1988:70–1. and impaired pancreatic exocrine function impairment 13 12 Weaver LT, Amarri S, Swart GR. C mixed triglyceride breath test. Gut remains poorly understood, although it seems reasonable to 1998;43:S13–19. propose that the enteroendocrine or neuroendocrine drive of 13 Sziegoleit A, Krause E, Klör HU, et al. Elastase 1 and chymotrypsin B in the pancreas by the duodenum is perturbed in some way. pancreatic juice and feces. Clin Biochem 1989;22:85–9. 14 Lankisch PG, Schmidt I, König H, et al. Faecal elastase 1: not helpful in Conclusion diagnosing chronic pancreatitis associated with mild to moderate exocrine pancreatic insufficiency. Gut 1998;42:551–4. This study supports the notion that small bowel mucosal 15 Löser C, Möllgaard A, Fölsch UR. Faecal elastase 1: a novel, highly integrity is necessary for normal control of exocrine pancre- sensitive, and specific tubeless pancreatic function test. Gut atic secretion. It highlights the need for gastrointestinal 1996;39:580–6. mucosal biopsy in individuals with reduced FE1 concentra- 16 Stein J, Jung M, Sziegoleit A, et al. Immunoreactive elastase I: clinical evaluation of a new noninvasive test of pancreatic function. Clin Chem tions in whom causes of primary pancreatic insufficiency 1996;42:222–6. (principally cystic fibrosis and Shwachman’s syndrome) have 17 Terbrack HG, Gürtler KH, Klör HU, et al. Human pancreatic elastase 1 been excluded. concentration in faeces of healthy children with cystic fibrosis. Gut 1995;37:A253...... 18 Stein J, Schoonbroodt D, Jung M, et al. Mesure de l’élastase fécale par immunoréactivité: une nouvelle approche indirecte de la fonction Authors’ affiliations pancréatique. Gastroenterol Clin Biol 1996;20:424–9. M G Schäppi, P J Milla, K J Lindley, Department of Gastroenterology, 19 Dominguez-Munoz JE, Hieronymus C, Sauerbruch T, et al. Fecal

Institute of Child Health and Great Ormond Street Hospital, London, UK elastase test: evaluation of a new noninvasive pancreatic function test. http://adc.bmj.com/ V V Smith, Department of Histopathology, Institute of Child Health and Am J Gastroenterol 1995;90:1834–7. Great Ormond Street Hospital 20 Soldan W, Henker J, Sprössig C. Sensitivity and specificity of D Cubitt, Department of Virology, Institute of Child Health and Great quantitative determination of pancreatic elastase 1 in feces of children. J Ormond Street Hospital Pediatr Gastroenterol Nutr 1997;24:53–5. 21 Carroccio A, Iacono G, Lerro P, et al. Role of pancreatic impairment in Research at the Institute of Child Health and Great Ormond Street growth recovery during gluten-free diet in childhood celiac disease. Hospital for Children NHS Trust benefits from R&D funding received from Gastroenterology 1997;112:1839–44. the NHS Executive. 22 Lankisch PG, Schmidt I. Fecal elastase 1 is not the indirect pancreatic 45

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